Film developing tank with rotatable film carrier



Nov. 21, 1950 R. l. SALZMAN 2,530,734

FILM DEVELOPING TANK WITH ROTATABLE FILM CARRIER Filed Nov, 4, 1947 2 Sheets-Sheet 1 99 7 98 96 1;? 94 I 1oz I 70 109 92 69 66 .III' 4 8 a4 .ZZZZII' 3 gv'wcmto r/ RALPH-l. SALZMAN Nov. 21, 1950 R. l. SALZMAN 2,530,734

FILM DEVELOPING TANK WITH ROTATABLE FILM CARRIER Filad Nov. 4, 1947 2 SheetsSheet 2 a .ll 1? 'm N 1 7 3 wu wtm fiALPH SALZMAN Patented Nov'. 21, 1950 UNITED STATES PATENT OFFICE FILM DEVELOPING TANK WITH ROTATABLE FILM CARRIER Ralph I. Salzman, San Pedro, Calif.

Application November 4, 1947, Serial No. 784,058

3 Claims. 1

This invention relates to film developing tanks and more particularly to a film developin tank which, though general in its application, is particularly adaptable to the development of 16- millimeter motion picture film, either black and white or colored. Furthermore, this invention is particularly related to such a motion picture film developing tank which may be used by the individual or amateur at home for amateur development of film.

It is a feature of the present invention that an entirely light-proof tank is provided in which is mounted a drum, on which the entire roll of motion picture film may be wound in such a position that the developing fluid has free contact with substantially all parts of the film.

It is another feature of this invention that the drum upon which the film is wound can be filled with water or other refrigerant liquid so as to control the temperature of the film and fluid during development.

It is another feature of this invention that the amount of developing fluid required is minimized.

It is another feature of this invention that a novel drainage device is employed for quickly removing the developing fluid at the desired time, and also for circulating a wash Water.

It is another feature of this invention that the entire film holding apparatus or tank is rotatably mounted to insure the intimate contact of the developing fluids and wash water with the film being treated.

It is another feature of this invention that whereas the developing tank is entirel lightproof, when desired, a light window is also provided for eflectuating a second exposure.

It is a further feature of this invention that the drum upon which the film is mounted may be inserted into the tank prior to being filled with the cooling fiuid, thus facilitating handling.

It is, accordingly, oneobject of this invention to provide a film developing tank of the type described embodying the above-mentioned advantages and features.

It is another object of this invention to provide a tank of the class described adaptable for the amateur development of either black and white or color motion picture film.

It is a further object of this invention to provide a film developing tank of the type described in which provision is made, after the insertion of the film into the lighttight tank, for the ap plication of a minimized amount of film developing fluid, after which provision is made for the the circulation of a wash water.

It is a further object of this invention to automatically control thetemperature of the film and developing fluid.

These and other advantages and features will be apparent from the annexed specification in which:

Figure l is a vertical section through a film developing tank embodying the present invention.

Figure 2 is an enlarged isometric, exploded fragmentary view of the bottom of the developing tank drum and center shaft.

Figure 3 is a plan view partly broken away and in section for clarity of description of the device, as shown in Figure 1.

Figure 4 is a fragmentary section taken along the line 4-4 of Figure 1.

Figure 5 is a fragmentary section taken along the line 55 of Figure 1.

Figure 6 is a detail perspective of a portion of the drum surface showing the film engaging strips.

Figure '7 is a fragmentary section taken along line l-1 of Figure 3.

Figure 8 is a fragmentary section taken along line 88 of Figure 3.

Figure 9 is a section taken along line 9-9 of Figure 8.

Figure 10 is a reduced fragmentary side elevation of the device shown in Figure 1.

Referring now more particularly to the drawings, there is shown a developing tank illustrated generally at 20. The tank 20 is generally cylindrical in form and is provided with a bottom wall 2|, the inner surface 22 of which member has a coniform taper sloping towards the center. The cylindrical wall of the tank '20 is enlarged at its upper end at 23 and a groove 24 is formed in the top portion thereof. The bottom 2| of the tank is provided with three depending legs 25, 26, and 21. On the left hand side the tank 20 is provided with a window 28, and a cover plate 29 adapted to form a light-tight seal about the window 28 is hinged adjacent the bottom of the tank as at 30, and a spring latch 3| is pivotally mounted as at 32 and provided with a portion 33 adapted to engage a pin 34 to removably retain the cover plate 29 in closed position. It will be noted that the window 28 extends substantially the full length of tank 20 so that when used to expose film mounted on the drum as hereinafter described a complete exposure is obtained.

The bottom Of the tank 20, adjacent the center portion thereof. is provided with a boss 35 having a central bore 36 therein, and a plurality of channels 38 communicating the bore 36 with the interior of the tank 20. The bottom 21 of the tank is also provided with an extension forming a channel 4 I. The bore 36 communicates with the channel 4|, as is shown more clearly in Figure 8. The channel 4| extends to the side of the tank 29 and throughout its length is provided with a plurality of bafiles 42 disposed at an angle to the longitudinal direction of the channel, and having their inner ends 43 extending far enough so as to overlap each other and thus prevent the entrance of any light through the channel 4| upwards through the bore 36 into the developing tank.

The outer end of the channel is threaded as at 44 for the reception of a spigot 45. The spigot 45 may be provided with any suitable valve mechanism, here shown as a valve 41 seated on a valve seat 48 and controlled by a knurled thumb screw 49 threaded into the valve housing as at 50.

A film holding drum 52 is providedgenerally cylindrical in form and having a coniform bottom Wall 53 and a similar coniform top wall 54. The

drical surface of the drum 52 is provided with a I plurality. of vertically extending ribs 69 suitably fastened on the exterior of the drum, each of which ribs is provided with a plurality of spaced blocks 6|, thus forming a channel 62 between each of the'blocks El. The ribs 60, with their. blocks 6!, are so disposedupon the exterior of the drum 52 as to form a helically wound channel extending from adjacent the button 63,

adjacent the upper lefthand corner of the drum,

as shown in Figure 1, to the button 64 adjacent the lower right hand corner of the drum. The buttons 63 and 64 are adapted to engage a suitable hole or slot in the film 65, which film will then be wound in the helical channel formed as aforesaid, and may extend the full extent of the drum from the button 63 to the button 64 in one continuous spiral. Further. as will be apparent from Figure 5, when the film 65 is so mounted on the drum it is spaced from the wall of the drum,

by virtue of the ribs 66, so that the develo ing fluid and wash water obtain free access to both sides of the film.

' The top 54 of the tank of the drum 52 is provided with a pair of upstanding cylindrical projections 66 and 61 spaced apart as shown, and a plurality of holes 58 and 69 are formed adjacent the bottom of said projections to drain the space therebetween. The top 54 is also provid-d with an upwardly extending post or hub 10. The hub 18 is provided in its upper end with four grooves H and a pulley 12 is provided, which pulley has a coniform hub section 73, the bottom portion 74 of which is provided with four tongues 15 adapted to Slldll'lfly en age in the grooves H, thus removably mounting the pulley 12 on the hub lll. A plurality of openings 16 are provided in the coniform section of the pulley l2 and the pulley I2 is provided with a belt groove H for connection to a belt 18 which may in turn be in operative connection with any suitable source of power such asan electric motor or the like.

The hub it has a hollow int rior and a spider iiflprovided th r in, the central portion 81 of which is internally threaded to receive the threads 8 2 forrned upon the central shaft 83, and

a second spider 8 is provided forming a bearing 85 for the shaft 83 and serving together with the threaded portion of the spider 3D to align the shaft 83 so that the lower end thereof will align with its reduced portion Bl firmly seated in sealing relation on the shoulder 58 formed in the enlarged portion 5'! of the bore 55. A thumb screw 88 may be provided on the upper end of the shaft 83 for turning the shaft The tank 26 is also provided with a removable lid 93, which lid has a depending flange 9i, offset from which is a depending rim 32 adapted to fit into the groove 2 in the enlarged portion 23 of the walls of the tank. The underside of the lid 93 --'is provided adjacent to the center thereof with a depending rim 93 adapted to lie in the annular space formed between the cylindrical projections E6 and 62' when the rim is in place, as clearly indicated in Figure l. The lid 51) is also providedwith alight-proof filling spout 94 positioned in an opening 95in the lid 99. The spout 9 comprises end walls 95 and 92' and side walls 33 and 99 affixed between upstanding flanges I30, Hit, 152 and H33 formed in the top of the lid adjacent the opening 95. The spout 94 also includes a pair of opposed, downwardly and inwardly extending baifles tilt and 885 below and spaced from which is a plate E98 spaced from the walls 96 and Ell, but attached to the walls 55 and 99; as indicated in Figures 1 and 7. Below the plate 106 is another pair of downwardly and inwardly ex-- tending baffles Nil and 68. The entire system of bafiles :03 and 05, plate 583, and baffles It! and E38 form, as will be understood, a light-proof filling spout.

The lid 98 also has a plurality of outwardly and downwardly extendin holes I89 formed adjacent the hub it and an upstanding rim or hub H! is formed on the lid as indicated.

The operation of the device is as follows: The exposed film B5 is wound upon the drum by attaching one end to the button 63 and winding the film in the channel 62 until the desired amount of film has been wound upon the drum. This operation, of course, will take place in a dark room. The drum 52 is then inserted into the tank 20 with the post 55 fitting into the bore 35, as indicated in Figure l. The lid is then applied and the entire structure is at this point safe for exposure to light providing, however, that the cover plate 29 is in closed position. The shaft 83 is next inserted and the threads 82 made up to force the reduced portion 8'! into firm sealing engagement with the shoulder 58 so as to prevent fluid from escaping from the interior of the drum. The drum 52 may now be filled with water or other suitable cooling fluid. It has been discovered that when ordinary tap water is used at the average temperature of'63", due to the large amount of water which is storedin the drum 52 the temperature of the developing fluid will remain at substantially 68 throughout the'deveh oping process. The water is inserted by pouring the same throughthe interior of the hub 79, passing down by the spiders 8d and 85. When this has been accomplished the developing fluid be inserted simply bypouring into the spout the desired measured amount of developing fluid.

It will be noted that due to the small space which is left between the interior portion of the walls of the'tank 28 and the outer portion. of the drum 52, only a very small amount of developing fluid will suffice to cover the entire film up to the level l 12. With the developing fluid thus located in the tank the drum 52 may then be rotated, either by hand, by turning on the hub 19 or, if desired, the pulley 12 may be slipped over the hub and attached to the belt '13 and driven by the power supply. When the required period of time for developing of fiuid has passed the operator will open the valve 47 allowing the developing fluid to drain through the channel 38, the bore 30, into the channel ll, and out the spigot 45 and a fixing fluid is supplied through the spout 3 and subsequently similarly drained ofi. Next, the lid 90 may be removed and the operator may continue to supply water to the interior of the hub '53 until the same overflows, flowing over the top 34 and washing the film 65.

Finally, the drum 52 may be drained by unscrewing the shaft 83 and lifting the portion 31 thereof from the shoulder 58, allowing the water to drain through the bore 56 into the channel t i.

In developing some types of film, prior to the Washing operation, it is desired to expose the film. This may, of course, be accomplished by unlatching the portion 33 from the pin 34, opening the cover plate 29, and applying light to the Window 28 while revolving the drum.

I have discovered that with the developing tank of this invention it is possible to develop motion picture film either in black and white or color very economically due to the small amount of developing fluid required, and with a great deal of safety due to the fact that the temperature is automatically maintained by the amount of fluid maintained within the drum 52.

While there has been described What is at present considered a preferred embodiment of the invention it will be understood that various changes and modifications may be made without departing from the essence of the invention, and it is intended to cover herein all such changes and modifications as come Within the true spirit and scope of the appended claims.

What is claimed is:

1. A film developing apparatus comprising: a cylindrical tank, a cylindrical drum of slightly smaller external diameter than the internal diameter of said tank rotatably disposed within said tank with its axis disposed vertically, a spiral film mounting track on said drum, a removable lid on said tank having means adapted to cooperate with means on said tank to exclude light therefrom, means defining a light-tight opening in said lid for filling the annular space between said drum and said tank with developing fiuid, a post in the bottom of said tank bored to form a bearing and a drain, a boss centrally disposed on the bottom of said drum pivotally seating in said bearing, a bore in said boss communicating with the bore in said post and a central shaft in said drum removably seating in said bore in said boss and sealing the same.

2. A film developing apparatus comprising: a cylindrical tank, a cylindrical drum of slightly smaller external diameter than the internal diameter of said tank rotatably disposed within said tank With its axis disposed vertically, a spiral film mounting track on said drum, a removable lid on said tank having means adapted to cooperate with means on said tank to exclude light therefrom, means defining a light-tight opening in said lid for filling the annular space between said drum and said tank with developing fluid, means defining a light-tight opening for filling said drum with water whereby said developing apparatus is maintained at substantially the temperature of said water, a post in the bottom of said tank bored to form a bearing and a drain, a boss centrally disposed on the bottom of said drum pivotally seating in said bearing, a bore in said boss communicating with the bore in said post and a central shaft in said drum removably seating in said bore in said boss and sealing the same.

3. A film developing apparatus comprising: a cylindrical tank, a cylindrical drum of slightly smaller external diameter than the internal diameter of said tank rotatably disposed Within said tank with its axis disposed vertically, a spiral film mounting track on said drum, a removable lid on said tank having means adapted to cooperate with means on said tank to exclude light therefrom, means defining a light-tight opening in said lid for filling the annular space between said drum and said tank with developing fluid, means defining a light-tight opening for filling said drum with water whereby said developing apparatus is maintained at substantially the temperature of said water, a post in the bottom of said tank bored to form a bearing and a drain, a boss centrally disposed on the bottom of said drum pivotally seating in said bearing, a bore in said boss communicating with the bore in said post, a central shaft in said drum removably seating in said bore in said boss and sealing the same, and means defining a light-tight drain for draining said tank.

RALPH I. SALZMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,213,489 Binder Jan. 23, 1917 1,440,644 Stromberg Jan. 2, 1923 1,441,163 Martin et al Jan. 2, 1923 1,750,704 Cante Mar. 18, 1930 1,898,218 Schroeder Feb. 21, 1933 1,979,106 Henderson Oct. 30, 1934 2,142,881 Bell Jan. 3, 1939 2,194,603 Lingg et al Mar. 26, 1940 2,298,963 Naylor Oct. 13, 1942 FOREIGN PATENTS Number Country Date 137,703 Great Britain Jan. 22, 1920 560,005 Great Britain Mar. 15, 1944 

